REPORT 


JAS.  D.  SCHUYLER, 


CONSULTING  ENGINEER. 


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PUEBLO  GRAVITY  WATER  COMPANY. 


REPORT  OF  CONSULTING  ENGINEER. 


Denver,  Colorado,  September  18,  1890. 


Directors  Pueblo  Gravity  Water  Company: 


Gentlemen — At  your  invitation  I  have  recently  examined 
the  field  of  operations,  which  you  have  undertaken  with  a  view 
of  determining  the  feasibility  and  cost  of  developing  and  con¬ 
veying  to  Pueblo  an  ample  supply  of  pure  filtered  water,  suffi¬ 
cient  for  the  wants  of  that  flourishing  city  for  years  to  come,  and, 
as  you  requested,  herewith  submit  my  report,  embodying  my 
views  of  the  project. 

The  painstaking  and  intelligent  manner  in  which  your  en¬ 
gineer,  Mr.  D.  C.  Henny,  has  performed  the  preliminary  studies 
of  the  situation,  has  enabled  me  to  obtain  a  thorough  insight 
into  the  scheme  without  loss  of  time  in  groping  for  necessary 
information.  I  have  reviewed  his  work  very  carefully,  and 
take  pleasure  in  commending  it  for  thoroughness  and  accura¬ 
cy  in  every  detail. 

Pueblo  is  a  city  of  nearly  30,000  inhabitants,  supported 
by  a  network  of  railroads  and  extensive  manufacturing  indus¬ 
tries.  The  start  which  it  has  made  in  manufacturing,  and  its 
advantageous  position  as  a  railroad  center,  seem  to  point  to  a 
steadily  progressive  growth  in  wealth  and  population.  The 
demand  for  a  water  supply,  superior  in  quality  and  volume  to 
that  at  present  available,  is  urgent,  and  the  field  for  new 
works  is  promising  and  lucrative.  The  present  supply  is  de¬ 
rived  from  the  Arkansas  River,  immediately  above  the  city, 
and  is  pumped  to  the  consumers.  The  river  is  a  turbid 
stream,  never  clear  and  pure,  but  carrying  a  fine  silt  in  sus- 


94 1 ! 56 


—  4  — 


pension,  which  seems  to  defy  all  the  efforts  thus  far  made  to 
settle  and  clarify  it.  The  works  in  North  Pueblo  (north  of 
the  river)  are  owned  and  operated  by  the  city,  under  the 
management  of  a  Board  of  Trustees.  In  all  respects,  as  near¬ 
ly  as  I  can  learn,  the  works  fail  to  satisfy  the  wants  of  the 
community ;  whether  from  faulty  management,  insufficient  ca¬ 
pacity,  inadequate  fire  pressure,  excessive  cost  to  the  taxpayer, 
impure  quality  of  the  water,  or  a  combination  of  all  these  de¬ 
fects,  the  fact  remains  that  the  existing  order  of  things  de¬ 
mands  a  radical  change. 

It  is  your  desire  to  bring  about  this  change  by  the  in¬ 
troduction  of  clear,  pure  water,  which  shall  flow  into  the  city 
by  gravity  from  an  elevation  sufficient  to  give  ample  fire 
pressure,  and  in  quantity  sufficient  to  respond  to  any  draft 
that  may  be  made  upon  it.  If  you  succeed  in  carrying  out 
your  plan,  the  investment  would  seem  to  be  a  highly  lucra¬ 
tive  one,  and  entitle  you  to  the  grateful  patronage  of  the  en¬ 
tire  community,  as  well  as  a  liberal  subsidy. 

The  source  of  your  water  supply  is  the  under-flow  of  Fon¬ 
taine  qui  Bouille,  which  you  propose  to  draw  out  by  means  of 
drain  pipes  of  large  size,  to  be  laid  across  the  subterranean  chan¬ 
nel  on  the  bed  rock  or  clay  sub-floor  of  the  valley. 

Overlying  this  floor  are  beds  of  coarse,  saturated  gravel, 
which  extend  up  the  stream  some  thirty  miles,  to  and  above 
Colorado  Springs,  as  well  as  for  some  distance  up  all  the  tribu¬ 
taries.  The  spot  selected  for  this  development  work  is  near 
Wigwam  station  on  the  Denver  &  Bio  Grande  Railroad,  some 
nineteen  miles  above  the  mouth  of  the  stream  at  Pueblo,  where 
you  have  purchased  sufficient  land  to  give  you  control  of  the 
major  part  of  the  water  bearing  gravel  beds,  from  side  to  side  of 
the  valley.  The  elevation  of  the  surface  here  is  about  5,200  feet 
above  sea  level,  or  540  feet  above  the  level  of  ordinary  low  water 
in  the  Arkansas  at  Santa  Fe  Avenue,  and  525  feet  above  the 
principal  business  streets  of  the  city. 

The  fall  given  to  the  main  conduit,  from  the  collecting  well, 
into  which  all  the  drains  empty,  to  the  distributing  reservoir  in 
North  Pueblo,  a  distance  of  75,380  feet,  is  216  feet,  or,  on  an 
average,  15.1  feet  per  mile.  The  depth  of  the  reservoir,  as  plan¬ 
ned,  is  twenty  feet,  and  the  height  of  the  bottom  of  the  reservoir 
above  the  main  streets  of  the  city  is  258  feet,  which  will  afford 


) 


more  than  100  pounds  pressure,  after  deducting  friction  in  the 
distributing  mains.  Hence  it  will  be  seen  that  the  elevations 
are  extremely  favorable,  and  water  can  be  thrown  all  over  the 
mesa  of  South  Pueblo  with  good,  ordinary  pressure. 

The  explorations  made  by  Mr.  Henny  by  means  of  boring 
at  intervals  across,  as  well  as  parallel  with  the  valley,  have 
shown,  that  the  hard  clay  bottom  beneath  the  gravel  is  from  ten 
to  forty-four  feet  below  the  surface,  and  is  shaped,  as  one  might 
expect,  like  a  large  trough,  5,000  feet  wide,  the  deepest  part  being 
on  the  east  side,  east  of  the  present  surface  channel.  This  trough 
is  filled,  heaping,  with  gravel,  over  which  lies  the  surface  soil  of 
adobe. 

The  permanent  water  level,  as  shown  by  the  borings,  is  not 
really  a  level  line  but  inclines  toward  the  lowest  part  of  the  trough, 
almost  parallel  with  the  clay  bottom.  The  thickness  of  the  clay 
sub-stratum  is  unknown,  although  one  of  the  borings  pierced  it 
for  sixty-six  feet  without  change.  It  is  identical  in  character 
with  that  found  underlying  the  whole  country  in  this  region  east 
of  the  Rockies,  and  is  locally  recognized  as  the  bed  rock  of  the 
country,  so  thick  and  so  dense  as  to  permit  no  water  of  streams 
flowing  over  and  upon  it  to  escape  by  percolation  through  it. 
Hence  all  the  water  of  the  stream  not  visible  upon  the  surface 
must  flow  along  this  clay  trough  through  the  gravel  contained 
in  it. 

The  borings  were  so  carefully  made,  that  a  contour  map  of 
the  clay  bottom  was  prepared,  from  the  data  so  furnished,  which 
shows,  that  while  the  slope  of  the  clay  bed  is  not  entirely  uni¬ 
form,  it  is  generally  parallel  with  the  surface  slope  of  the  valley, 
whose  average  inclination  is  about  30  feet  per  mile. 

The  total  cross-sectional  area  of  the  gravel  beds  below  the 
permanent  water  line,  on  the  section  selected  for  laying  the  drain¬ 
age  pipes,  is  66,600  square  feet,  which  gives  an  average  depth  of 
saturated  gravel  of  nearly  14  feet;  on  the  line  of  development, 
however,  the  depth  is  from  18  to  20  feet  from  the  water  line. 
The  development  immediately  proposed  will  drain  a  width  of 
2,400  feet  of  the  valley,  leaving  1,600  feet  on  the  west  side,  not 
directly  tapped,  of  sufficient  depth  to  be  desirable  for  future 
drainage,  although  the  pipe  to  be  immediately  laid  will  drain  a 
portion  of  this  also.  The  area  of  saturated  gravel  immediately 
over  the  2,400  feet  of  pipe  will  be  32,000  square  feet.  As  the  voids 


—  7  — 


in  the  gravel  compose  about  three-tenths  of  the  mass,  the  water 
filling  these  voids  must  be  a  very  considerable  volume,  if  it  were 
possible  to  determine  its  mean  velocity.  Lying  as  it  does  on  such 
a  steep  slope,  it  is  impossible  to  imagine,  that  the  water  is  standing 
still,  but  it  must  have  a  constant  movement  down  the  slope  pre¬ 
cisely  as  though  the  gravel  did  not  exist,  although,  of  course,  enor¬ 
mously  retarded  by  the  friction  of  the  gravel.  This  movement 
is  proven  by  the  results  of  the  small  development  work  already 
done,  by  which  you  have  succeeded  in  drawing  out  about  500,000 
gallons  daily  from  a  pipe  200  feet  long,  laid  3J  to  6  feet  below  the 
surface.  The  rate  of  flow,  and  consequently  the  volume  of  water, 
which  you  may  expect  to  develop  from  your  works,  which 
is  the  vital  point  in  the  whole  question,  cannot  be  definitely 
measured,  estimated  or  foretold  There  must  be  an  element 
of  chance  in  this  part  of  the  scheme.  All  that  I  can  say  in 
the  matter  is,  that  the  probabilities  seem  to  point  to,  a 
flow  of  ten  to  twelve  million  gallons  daily  as  the  result 
of  your  first  work,  and  about  twenty  millions  as  the  maxi¬ 
mum  obtainable  from  the  complete  sub-drainage  of  the  valley. 
I  arrive  at  these  conclusions  from  a  consideration  of  all  the  con¬ 
ditions  that  combine  to  produce  the  results — the  great  area  of 
water  shed,  the  rain  fall,  the  extent  of  the  gravel  beds  of  the 
stream  and  its  tributaries  and  the  fact,  that  the  surface  stream  is 
practically  dry  a  considerable  part  of  the  year,  for  some  distance 
above  and  all  the  way  below  your  head  works,  except  where  springs 
appear  and  are  drawn  off  by  irrigation.  It  is  my  experience  with 
Californian  streams,  that  they  invariably  sink  and  disappear  in 
their  beds,  wherever  large  gravel  and  sand  deposits  occur,  except 
in  flood  time,  and  the  development  of  the  under-flow  is  regularly 
and  widely  practiced  by  shallow  cuts  and  tunnels,  with  gratifying 
results. 

The  area  of  water  shed  of  the  Fountain  and  its  tributaries 
above  Wigwam  is  807  square  miles,  including  Pike’s  Peak,  Chey¬ 
enne  Mountain,  Cameron’s  Cone  and  the  Rampart  Range,  where 
the  precipitation  of  snow  and  rain  is  heavy,  besides  the  elevated 
plateau,  known  as  the  Great  Divide.  This  water  shed  area  is 
about  double  that  of  Cherry  Creek,  which  has  no  mountain  drain- 
oge  and  depends  solely  upon  the  Divide  for  its  supply,  and  yet 
the  Denver  Water  Company  is  expending  some  two  million  dollars 
in  developing  the  sub-flow  of  the  stream,  which  they  hope  will 
reach  50,000,000  gallons  daily. 


—  8  — 


However,  the  area  of  drainage  is  not  so  important  as  the 
area  and  volume  of  the  gravel  beds  that  carry  the  sub-flow,  ex¬ 
cept  that  every  little  stream  from  the  mountains  constantly  con¬ 
tributes  its  quota  toward  maintaining  the  saturation  of  the 
gravel  beds  in  the  dryest  time  of  the  year,  and  the  sum  of  them 
all  is  evidently  to  be  encountered  by  a  cross  cut  of  the  valley  at 
Wigwam. 

A  conservative  estimate  of  the  extent  of  the  saturated  gravel 
strata  above  Wigwam  would  be  a  length  of  twenty-five  miles,  a 
width  of  2,000  feet,  and  a  depth  of  twelve  feet.  Considering  this 
as  a  reservoir  filled  once  a  year,  for  example,  the  volume  of  water 
it  would  contain  would  be  about  7,000,000,000  gallons ;  sufficient 
to  yield  20,000,000  gallons  daily.  Of  course  it  would  be  impossi¬ 
ble  to  drain  it  entirely,  and  on  the  other  hand  during  the  five  or 
six  months  when  the  surface  stream  was  flowing,  the  amount  that 
had  been  drained  would  be  refilled  and  the  daily  draft  steadily 
restored  by  percolation  from  the  stream. 

Experiments  made  by  Mr.  Henny  at  Wigwam,  which  were 
confirmed  by  the  observations  of  flow  from  development  works 
on  Monument  creek,  led  him  to  conclude,  that  on  that  slope  water 
found  its  way  through  the  gravel  at  the  rate  of  about  seven  feet 
per  hour.  On  this  basis,  the  area  of  the  voids  in  the  saturated 
gravel  cross-section  at  Wigwam  would  carry  about  24,000,000 
gallons  daily.  I  arrived  at  a  similar  result  by  another  process. 
Hence,  as  I  have  said,  although  there  is  a  certain  element  of 
chance  and  uncertainty,  the  probabilities  point  to  a  yield  of 
about  the  quantities  named,  if  the  development  work  is  carried 
out  in  a  thorough  manner. 

The  plan  proposed  by  Mr.  Henny  for  this  development  seems 
to  me  to  have  been  well  digested. 

Starting  at  a  point  down  the  stream,  where  the  required  grade 
from  the  bottom  of  the  collecting  well  approaches  the  surface,  he 
proposes  to  make  an  open  cut  about  5,600  feet  in  length,  wide 
enough  to  carry  two  lines  of  thirty  inch  wooden  pipe,  both  of 
which  are  to  be  laid  at  once  to  the  collecting  well,  although  but 
one  of  them  will  be  used  immediately.  These  pipes  will  be  cov¬ 
ered  as  laid,  and  serve  to  drain  off  the  water  from  the  cross  cut 
above.  The  drainage  pipes  will  be  of  cement,  thirty  and  thirty- 
six  inches  in  diameter,  laid  with  open  joints  to  admit  of  the  tree 
assage  of  water.  They  will  act  precisely  like  ordinary  drain 


Collect/ at g  Well. 

Scale  8  Ft:.  =  1  In. 


Surface  of  Ground  5/89  If  Above  SeoUei/el 


Vertical  Section . 


— 11  — 


tile,  only  on  a  larger  scale.  They  will  not  follow  straight  lines 
across  the  valley,  but  be  laid  on  grades  sufficient  to  freely  dis¬ 
charge  their  contents  into  the  collecting  well.  Two  lines  of  drain 
pipe,  each  400  feet  long,  will  be  projected  up  the  valley,  one  on 
the  west  side,  the  other  near  the  lowest  depression  ot  the  clay 
floor.  The  water  will  naturally  seek  the  freest  and  easiest  exit, 
which  will  be  afforded  by  the  drains,  and  it  is  not  anticipated 
that  any  considerable  quantity  will  pass  the  intercepting  drain, 
although  a  tight  line  of  sheet  piling  and  a  puddle  dam  up  as 
high  as  the  present  water  level  will  be  put  in  after  the  drain  pipe 
is  laid. 

This  cement  pipe  can  best  be  made  on  the  ground,  as  all  the 
materials  except  cement  are  abundant,  and  the  manufacture  of  it 
should  be  begun  without  delay.  The  amount  required  is  800 
feet  of  thirty-six  inch,  and  3,600  feet  of  thirty  inch. 


THE  MAIN  CONDUIT. 


The  survey  for  the  main  pipe  line  from  the  head  works  to 
the  distributing  reservoir  located  in  North  Pueblo  Heights,  skirts 
along  the  low  hills  on  the  west  side  of  the  valley,  by  a  very  di¬ 
rect  line.  The  original  survey  located  the  reservoir  seventy-five 
feet  higher  and  some  6,000  feet  further  from  the  city  than  its 
present  location,  but  at  my  suggestion  this  was  changed,  as  it 
was  apparent  that  the  elevation  of  the  reservoir  was  greater  than 
was  desirable,  requiring  the  introduction  of  expensive  pressure 
valves  for  the  safety  of  the  plumbing  in  the  city.  The  pressure 
to  be  borne  by  the  conduit  was  thereby  greatly  reduced,  and 
its  cost  somewhat  lessened. 

The  following  table  shows  head  of  pressure  on  the  pipe, 
as  now  located  : 


Length. 
300  feet, 
7,000  “ 
23,090  “ 
15,100  “ 
8,950  “ 
3,600  “ 
6,100  “ 
3,350  “ 
1,900  “ 
750  “ 


Head  of  pressure. 

0. 

0  to  10  feet. 

10  to  20  “ 

20  to  30  “ 

30  to  40  “ 

40  to  50  “ 

50  to  60  “ 

60  to  70  “ 

70  to  80  “ 

80  to  90  “ 


Wooden  Pipe 

laid  by 

the  Denver  Water  Company! 

in  1335. 


Tte  DenvEr  Lith.Ca. 


—  14  — 


I  have  recommended  the  use  of  5,630  feet  of  30  inch,  and  the 
remainder,  70,140  feet,  of  24  inch  pipe  to  be  made  of  California 
red  wood  stayes,  built  continuously  in  the  trench  and  banded  with 
round  steel  bands.  This  recommendation  has  been  made  for  the 
following  reasons : 

First — After  thoroughly  investigating  the  history  of  wooden 
pipe  as  laid  for  seven  years  past  in  Colorado,  and  after  examining 
a  number  of  lines  in  use,  I  have  come  to  the  conclusion,  that  if 
the  bands  are  properly  coated  and  the  pipe  kept  full  of  water  it  is 
practically  indestructible,  and  certainly  has  a  longer  life  than 
sheet  iron  or  steel  riveted  pipe. 

Second — The  interest  on  the  difference  in  cost  between  wood 
and  cast  iron  pipe  of  the  same  capacity  will  replace  the  wood  pipe 
every  ten  years,  which  I  think  is  but  a  fraction  of  the  life  of  wood 
pipe,  and  therefore  it  would' be  a  prodigal  waste  of  money  to  put 
the  amount  of  capital  necessary  to  lay  cast  iron  mains  into  the 
enterprise. 

Third — The  wood  pipe  is  cleaner,  does  not  become  foul,  does 
not  rust,  does  not  fill  with  tubercles  that  diminish  the  capacity 
year  by  year,  has  no  yarn  to  rot  and  contaminate  the  water,  will 
not  break  by  settlement,  will  not  burst  so  readily  under  water 
hammer,  and  so  long  as  it  lasts  is  in  every  respect  cleaner  and 
more  desirable. 

It  has  been  made  to  stand  180  feet  head,  without  leaking,  or 
double  the  maximum  pressure  on  your  pipe.  California  redwood 
is  so  much  better  adapted  to  that  purpose  than  any  other  wood 
available,  that  I  recommend  that  material. 

The  capacity  of  the  conduit,  I  estimate  at  11,000,000  gallons 
dailv. 

THE  DISTRIBUTING  RESERVOIR, 
has  been  located  on  blocks  50  and  71,  North  Pueblo  Heights, 
19,000  feet  distant  from  the  Arkansas  river.  The  ground  selected 
is  of  sufficient  area  to  construct  two  additional  reservoirs  of  the 
same  capacity  as  the  one  estimated  upon,  which  is  to  hold  7,000,- 
000  gallons,  although  it  would  be  advisable  to  secure  high  ground 
in  another  part  of  the  city  for  a  second  reservoir,  when  the  first 
one  shall  have  become  insufficient.  The  function  of  these  res¬ 
ervoirs  is  to  equalize  the  flow  of  the  main,  to  relieve  the  pressure 
on  the  conduit,  which  direct  connection  with  the  distributing 
mains  would  involve,  and  to  hold  a  reserve  supply  with- 


—  16  — 


in  the  city  limits  for  emergencies.  The  rate  of  consumption 
varies  throughout  the  day.  At  night  it  may  be  but  10  per  cent, 
of  the  average,  and  during  certain  hours  of  the  day  it  may  be  two 
or  three  times  the  average.  The  reservoirs  serve  to  preserve  the 
equilibrium,  and  cannot  be  too  large  within  reasonable  limits. 

It  is  contemplated  to  excavate  the  reservoir  with  side  slopes 
of  1  to  1,  building  up  the  excavated  earth  into  an  embankment  3 
feet  higher  than  the  high  water  line,  and  paving  the  slopes  with 
rock  or  slag,  covered  with  asphaltum  1  inch  thick.  The  depth  of 
water  will  be  20  feet.  The  whole  reservoir  will  be  covered  with 
a  corrugated  iron  roof,  resting  on  wooden  girders,  and  supported 
by  creosoted  wooden  posts.  This  roof  will  effectually  exclude  the 
light  and  prevent  the  growth  of  algea  in  the  water. 

The  pipe  to  connect  the  reservoir  with  the  city  main  on  Tenth 
Street  will  be  19,000  feet  in  length,  and  have  a  maximum  pressure 
of  113  lbs.,  static  head,  per  square  inch.  The  estimate  has  been 
made  for  the  use  of  heavy  sheet  riveted  pipe  for  this  line,  to  be 
coated  with  the  latest  improved  asphalt  pipe  dip. 

I  have  been  unable  to  learn  the  present  consumption  in 
Pueblo,  but  I  judge  it  to  be  little  short  of  4,500,000  gallons  daily. 
With  a  conduit  having  a  capacity  of  11,000,000  gallons  leading 
to  the  city,  the  generosity  of  the  provision  for  future  growth 
cannot  be  questioned.  I  should  not  deem  it  wise,  however,  to 
reduce  the-  capacity  of  the  conduit  below  11,000,000  gallons. 

The  only  other  sources  of  clear  watter  supply,  which  are  at 
all  available  for  the  city  and  which  can  be  looked  upon  as  possi¬ 
ble  future  rivals,  are  the  St.  Charles  river  and  Hardscrabble 
creek  on  the  south,  and  Beaver  creek  emptying  into  the  Arkan¬ 
sas  some  twenty-five  miles  west  of  Pueblo.  They  are  all  a  great 
distance  away  over  a  rough  country,  to  the  points  in  each  of  the 
streams,  where  a  satisfactory  supply  could  be  diverted,  and  if  my 
recollection  of  them  serves  me,  they  would  all  involve  the  neces¬ 
sity  of  great  storage  reservoirs  to  impound  the  surplus  flood  flow 
not  appropriated  for  irrigation.  It  does  not  seem  to  me,  that  any 
of  these  sources  are  to  be  feared  as  future  rivals.  On  the  con¬ 
trary,  it  would  appear,  that  the  sole  hope  of  a  clear,  pure  gravity 
water  supply  for  Pueblo  rests  on  the  construction  of  your  works. 

Faithfully  yours, 

JAS.  D.  SCHUYLER, 

Consulting  Engineer. 


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HttivcAsiry  of  illihou 


